I bought the '03 demo hardtail frame kit + wheels, back in December. The '04 is lighter, with alloy gears. Since then, I've had it in axle deep snow, water crossings, mud... in other word, pretty typical winter riding here.

Weight wise, the extra gears & drive train adds about a pound. Not bad. On smooth trails, you notice the gear-train noise when AWD is engaged. Disengaged, it runs quiet just like any bike. There is a slight but noticeable change in efficiency when switching to AWD. When engaged, the front drive train is driven at slightly less that 1:1, so it is not delivering power to the front wheel until the rear wheel starts slips. Thus on smooth trails, you don't notice anything except for the extra drivetrain noise.

In rock gardens, you can tractor over just about anything as long as you can keep pedaling and stay upright - no more momentum & body english to roll over multiple obstacles & gaps. It kind of feels like cheating. Even when you start to loose your balance, you can turn your handlebars, and drive the front wheel to pull you back up. In muddy climbs, it just keeps going as long as your legs hold up. You can climb steep hills covered with > 8" of snow - again if your legs hold out.

On downhills, the front wheel resists washouts extremely well by driving into the turns, as long as you keep the rear wheel turning. It was quite apparent in mud & snow. This would probably be a big advantage for gravity racers, if Christini would build a DH model.

Quirks: Torque steer - when the front drive engages, there is noticeable torque steering as power is transmitted down the steerer tube. In rock gardens, its hard to notice, but you can tell in smooth mud.

Because there is no differential, the front wheel gets driven anytime it rolls slower than the back, like cresting a ledge, or going over a large log. In these cases you feel the drag in the pedals, and one of the tires will skid to compensate.

The geared drive-train makes itself heard when the front wheel delivers torque, not loud, but noticeable.

The biggest detraction is it doesn't compensate for lack of skill or fitness! Bummer ;)

In general, I think most riders will not benefit much from the AWD, it only really becomes an advantage when you get into some nasty conditions. That being said, there is a certain local climb that has a crux that I had yet to clean, and the Christini rolled right up & over it. Also, there is a certain trail that is 5km of pretty continuous rock gardens - a dab-city type trail for hardcore riders, and the only reason that I dabbed with the Christini is that I ran out of legs. (actually, sometimes I just suck...)

Many of the locals have tried it out in the rock gardens and the response is very similar - "keeps going if you keep pedaling" and "feels like cheating..." The exposed gear train has survived without a problem, and we've bush-wacked it.

I'm not crazy about the White Brothers fork, the sliders get very stiff in cold weather (below freezing) so the fork is not very plush. In warmer temps, the fork action is acceptable ~ good. I've heard they are coming out with a better fork, so I'll probably upgrade when it comes out, especially as one of the main reasons I got it was for winter riding.

Other than the drivetrain quirks, the Christini successfully does what it was designed to. I'd recommend it for people who like to ride technical challenging trails.